Brain damage from hypoxia-ischemia represents a major health problem in pediatrics. At present, no method exists in clinical care to diagnose cerebral hypoxia-ischemia in real-time at the bedside, thereby limiting prevention and treatment of the brain damage. Near infrared spectroscopy (cerebral oximetry) is an emerging optical technology with the potential to fulfill this role. In previous work, we built a prototype frequency domain near infrared cerebral oximeter and found it measures cerebral O2 saturation accurately. However, before clinicians will use cerebral O2 saturation to diagnose cerebral hypoxia-ischemia, the measure needs to be related to other known measures of hypoxia-ischemia, and the instrument needs to be engineered to the clinical environment. This fast-track proposal will develop a frequency domain near infrared cerebral oximeter to diagnose cerebral hypoxia-ischemia in real-time at the bedside for pediatrics (<8 years). Instrument development includes construction of "user-friendly" hardware and software, evaluation of its performance in a simulated clinical environment, and identification of critical cerebral 02 saturation-in piglets to diagnose hypoxia-ischemia. The instrument will be operable by the nurse caring for the child at the bedside and will display cerebral O2 saturation and messages to facilitate its operation. PROPOSED COMMERCIAL APPLICATION: The cerebral oximeter will be used in children at risk of hypoxic-ischemic brain damage. The population at risk, encompassing about 5% of pediatrics, includes sick premature infant and lull term infants, as well as children with congenital heart disease, sickle cell anemia, seizure disorders, or meningitis. The market is enormous as it consists of all hospitals and freestanding clinics treating this population.